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Biomedical subjects

J M Sullivan

Publications and source records attributed to J M Sullivan.

At least 181 records · Page 10Linked to original sources
PubMed1967

Regional myocardial blood flow.

A method is described which measures the local effectiveness of the myocardial circulation, expressed as a clearance constant. Uniform clearance constants have been demonstrated in the normal canine and human myocardium. A distinct difference in clearance constants has been demonstrated between the normal canine myocardium and areas of naturally occurring disease. Heterogeneous clearance constants have been found in a majority of human subjects with coronary artery disease-the lowest rates being noted in areas of fibrous aneurysm.

Aneurysm↗
PubMed1967

Brain metabolism during fasting.

Catheterization of cerebral vessels in three obese patients undergoing 5-6 wk of starvation demonstrated that beta-hydroxybutyrate and acetoacetate replaced glucose as the predominant fuel for brain metabolism. A strikingly low respiratory quotient was also observed, suggesting a carboxylation mechanism as a means of disposing of some of the carbon of the consumed substrates.

Acetoacetates↗
PubMedDate not supplied

Interrelationships among thiazide diuretics and calcium, magnesium, sodium, and potassium balance in normal and hypertensive man.

The benzothiadiazide diuretics are known to cause magnesium and potassium wasting and retention of calcium and uric acid. The effect of magnesium replacement on diuretic-induced changes in sodium, potassium, calcium, and magnesium balance, weight, and blood pressure was studied in 12 normal subjects and 13 hypertensive patients to determine whether oral magnesium would reduce thiazide-induced kaliuresis. The groups differed in their response to diuresis in that the normotensive subjects did not show a fall in blood pressure (despite an equivalent weight loss), returned to a state of sodium balance earlier, and developed a greater net negative potassium balance over 12 days of diuretic therapy. Both groups displayed calcium and uric acid retention and magnesium wasting during diuretic therapy. The addition of oral magnesium replacement during diuretic therapy had no effect on any measured values beyond that seen in subjects who took diuretics without magnesium replacement. Thus, magnesium replacement did not reduce urinary potassium loss. However, urinary calcium losses increased when magnesium was given to subjects who were not receiving diuretics. The data provide the first report that small doses of oral magnesium enhance calcium excretion in hypertensive subjects.

Adult↗
PubMedDate not supplied

Osteoporosis as a model for the long-term clinical consequences of the menopause.

The decrease in ovarian function culminating in the last menstrual period, the menopause, in women in their forties and fifties takes place over a period of 3 to 5 years. There are several immediate clinical consequences of the menopause that are easy to detect and treat, usually with hormone replacement. In contrast, the longer term consequences of the menopause, cardiovascular disease and osteoporosis, are usually clinically silent during these early postmenopausal years. As a result, it has proven difficult to get physicians and their patients to accept this cause-and-effect relationship between the menopause and the development of osteoporosis or heart disease a decade or more later. The details concerning the menopause and osteoporosis are by now so well established that this disease can serve as a model for studies linking the menopause to heart disease. This article, with its focus on osteoporosis, serves as an introduction to the later articles detailing the cardiovascular consequences of the menopause.

Bone Remodeling↗
PubMedDate not supplied

Coronary arteriography in estrogen-treated postmenopausal women.

Four cross-sectional studies that used coronary arteriography to determine the extent of coronary atherosclerosis have provided some of the most convincing evidence that estrogen replacement reduces cardiovascular risk in postmenopausal women. One study of outcome in women undergoing coronary arteriography at baseline has found that the greatest improvement in total mortality occurred in women with significant coronary stenosis. Angiographic studies have also confirmed the importance of high-density lipoprotein in mediating the effect of estrogen and the beneficial effect of estrogen on endothelial function.

Clinical Trials as Topic↗
PubMedDate not supplied

Limited literacy revisited implications for patient education.

PURPOSE: It is important to determine whether teaching materials are understood and deemed accurate by the cancer patients being served. The authors used a series of patient participatory interviews to evaluate two brochures: Chemotherapy: What It Is and How It Helps by the American Cancer Society; and Helping Yourself During Chemotherapy: 4 Steps for Patients by the National Cancer Institute. The authors sought to determine whether 1) the brochures were clear; 2) differences in presentation were perceived by patients; and 3) differences influenced respondents' understanding and opinions of the brochures. DESCRIPTION OF STUDY: A qualitative, focus-group methodology was used. Twelve cancer patients, eight of whom were women and six of whom were African American, were recruited from three outpatient clinics. Participants ranged in age from 31 to 62 years of age, and in education from completion of ninth grade to graduate school. Patients participated in a series of five groups, with a series of semistructured questions about content and format being asked of each group. All sessions were audiotaped. The investigators reviewed data both independently and together to identify content and format evaluations. RESULTS: Findings showed that most participants were drawn first by the National Cancer Institute format; the American Cancer Society brochure was seen as having more information; the two brochures were seen as complementary; some confusion arose from the content of both brochures; and the discussions of emotional and sexual aspects were important. CLINICAL IMPLICATIONS: These findings support the need for simple, clearly written brochures rather than brochures of varying literacy levels. The confusion caused by differences in advice given by the two organizations indicates the need to address specific areas in which dissimilarities exist. Finally, the project demonstrates the utility of patient focus groups for evaluation of patient education material.

Adult↗
PubMedDate not supplied

Integrated treatment for the survivor of childhood trauma who is chemically dependent.

A substantial percentage of individuals who are chemically dependent also suffer from posttraumatic stress disorder and other survivor syndromes related to childhood abuse. The synergism of these multiple conditions creates unique treatment challenges. An enhanced, integrated treatment approach increases the chances of a successful clinical outcome. This article discusses a treatment model for chemical dependence and trauma-related syndromes that blends mental health and 12-Step and other chemical dependence treatment notions into an integrated approach that treats both disorders simultaneously and comprehensively. The model uses the strategic principle of "safety first" to drive all interventions and has five stages to organize the selection and timing of treatment tactics: crisis, skills, education, integration, and maintenance. This article also presents specific therapeutic tactics for each stage and a composit case example blending the history and recovery process of a survivor to illustrate the model in action.

Child↗
PubMedDate not supplied

Studies of the renin-renin substrate reaction in man; kinetic evidence for inhibition by serum.

Increasing evidence suggests that the renin-renin substrate reaction is regulated by factors other than the concentrations of enzyme and substrate. Partially purified human renin and renin substrate extracted from the plasma of each of eight human subjects were used to construct substrate-velocity curves comparing the rate of substrate cleavage in the whole serum of each individual with the rate in a corresponding system containing purified autologous substrate, or purified substrate plus a small amount of autologous serum. Linear regression analysis of the double reciprocal plots were used to compare the kinetic constants in paired experiments. Maximal reaction velocity (Vmax) was significantly lower (p greater than .05) when the reaction rate was measured in whole serum, in seven of the eight patients, while Km did not differ significantly, suggesting the presence of noncompetitive inhibition by human serum. The mean Michaelis constant in serum was 449 ng/ml while the average native substrate concentration of the five normal subjects was 629 ng/ml, an excess of less than twofold. The data suggest that plasma renin activity in man depends upon the concentrations of inhibitor and substrate, as well as upon the concentration of renin.

Angiotensin II↗
PubMedDate not supplied

Cellular and molecular mechanisms underlying learning and memory impairments produced by cannabinoids.

Why does smoking marijuana impair learning and memory? Behavioral studies suggest that a disruption of normal hippocampal function contributes to these deficits. In vitro experiments find that cannabinoid receptor activation reduces neurotransmitter release below the levels required to trigger long-term changes in synaptic strength in the hippocampus. Cannabinoids reduce glutamate release through a G-protein-mediated inhibition of the calcium channels responsible for neurotransmitter release from hippocampal neurons. These mechanisms likely play a role in the learning and memory impairments produced by cannabinoids and by endogenous cannabinoid receptor ligands.

Animals↗
PubMedDate not supplied

Learning the baby: a maternal thinking and problem-solving process.

PURPOSE: To describe a maternal problem-solving process from new mothers' day-to-day experience of caring for and developing a relationship with their babies. DESIGN: Qualitative study using grounded theory approach. SETTING: Mothers' homes (n = 23) and workplaces (n = 2). PARTICIPANTS: 25 mothers of babies from 2 weeks to 7 months. MAIN OUTCOME MEASURES: Semi-structured interviews. RESULTS: "Learning the Baby" was a major thinking process that emerged. Systematic thinking dominated mothers' problem-solving. Even after the babies were comforted, mothers were not certain their efforts alleviated the babies' problems, because they usually were not certain of the problem. CONCLUSIONS: Mothers' thinking directs their caregiving actions. The findings were related to previous problem-solving and women's thinking perspectives. Nurses must use planned and unplanned encounters effectively to collaborate with and teach mothers about baby behavior and health care.

Adult↗
PubMedDate not supplied

Hemodynamic and antihypertensive effects of captopril, an orally active angiotensin converting enzyme inhibitor.

Captopril inhibits angiotensin II formation and bradykinin degradation in vivo. Eleven patients with essential hypertension (EH) and four patients with renovascular hypertension (RVH) were treated with captopril for periods ranging from 3 days to 12 months. All patients had a diastolic blood pressure (DBP) over 95 mm Hg after receiving a placebo for 3 days. Captopril given in ascending doses (10-1000 mg/day) caused normalization of blood pressure in all but three patients, one with severe RVH whose pressure fell 11%, one patient with severe EH, whose pressure fell 27%, and one with EH whose blood pressure fell 8.5%. The average control DBP in patients with EH was 113.7 +/- 5.5 (SE) mm Hg and fell to 89.9 +/- 3.6 mm Hg (p less than 0.001), while DBP in patients with RVH fell from 110.7 +/- 7.6 mm Hg to 94.5 +/- 8.2 (p less than 0.005). All patients were studied in balance on a 100 mEq sodium (Na) diet. Plasma renin activity (PRA) versus 24-hour urinary Na excretion increased sevenfold during therapy while converting enzyme activity fell by about one half. The magnitude of the blood pressure response was not related to control PRA. Cardiac output was estimated by echocardiography during placebo administration and during maintenance therapy with captopril. A significant change was not observed. Total peripheral resistance fell an average of 18.9% (p less than 0.05) in 11 of the 13 patients in whom the measurement could be made. It is concluded that captopril effectively lowers blood pressure in patients with EH or RHV by reducing total peripheral resistance.

Adult↗
PubMedDate not supplied

Hemodynamic mechanisms of adaptation to chronic high sodium intake in normal humans.

The long-term hemodynamic effects of a high dietary sodium intake were studied in 10 young normal subjects. After a 4-day diet of 10mEq of sodium and 60 mEq of potassium per day the mean arterial blood pressure (MAP) was 82.3 +/- 15.1 mmHg, the cardiac index (CI) was 2.32 +/- 0.69 liter/min/m2, and total peripheral resistance (TPR) was 1778 +/- 947 dyne sec cm-5. After 4 to 6 days of 200 mEq of sodium and 60 mEq of potassium per day, MAP was 84.3 +/- 20.9 mm Hg, CI had risen to 2.53 +/- 0.61 liter/min/m2, and TPR fell to 1437 +/- 328 dyne sec cm-5. After 6 months of unrestricted sodium intake, urinary sodium excretion (UNa) was 144.1 +/- 51.9 mEq/24 hrs (p less than 0.001), MAP remained at 83.1 +/- 13.8 mm Hg, CI had risen to 3.11 +/- 1.01 liter/min/m2 (p less than 0.05) and TPR was 1268 +/- 444 dyne sec cm-5. After 12 months, UNa had risen to 171.5 +/- 97.6 mEq/24 hrs (p less than 0.005), while MAP remained at 82.4 +/- 17.9 mm Hg, CI at 3.08 +/- 1.16 liter/min/m2 (p less than 0.05), and TPR at 1282 +/- 500 dyne/sec/cm-5. Thus, cardiac index rises significantly with sodium intake in normal subjects and remains at a higher level for as long as 12 months. Blood pressure does not rise because TRP falls proportionately.

Adaptation, Physiological↗
PubMedDate not supplied

Attenuation of the microcirculation in young patients with high-output borderline hypertension.

Previous studies have shown abnormalities of the microvasculature in the spontaneously hypertensive rat and human subjects with established hypertension. We have studied the conjunctival microvasculature in relation to systemic and forearm hemodynamics in 24 normal subjects (NL) and 10 subjects with intermittent elevation of blood pressure (BHT). Macrophotographs of the conjunctival circulation were measured for arteriolar diameter and density of arterioles, capillaries, and venules. Blood pressure was measured by Arteriosonde, cardiac index by echocardiography, and forearm hemodynamics by mercury-filled strain-gauge venous occlusion plethysmography. Average diastolic blood pressure in the NL group was 74 +/- 1.7 mm Hg, while that of the BHT subjects was 89 +/- 3.1 mm Hg (p less than 0.005). Capillary density, venous density, and total vascular density were significantly lower in the BHT than NL group, while arteriolar density did not differ significantly. Cardiac index was significantly higher, and peripheral vascular resistance significantly lower, in the BHT as compared to the NL subjects. Forearm blood flow was higher in the NL subjects. The diameter of the preterminal arterioles of the BHT subjects was 27% greater than NL (p less than 0.02). The capillary density was inversely related to the cardiac index (r = -0.482, p less than 0.01), but was not related to blood pressure (r = -0.207). We conclude that the high cardiac output phase of early essential hypertension in humans is accompanied by a reduction in the number of filtering capillaries, and that the rarefaction of capillaries is more closely related to the elevation of cardiac output than to raised blood pressure.

Adult↗